Telephone-exchange system.



C. L. GOODRUM.

TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED MAR. 16. I915.

Patented May 30, 1916.

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TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED MAR-16.1915.

Patent-ed May 30, 1916.

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u N t CHARLES L. GOODRUM, OF NEW YORK, N. Y., ASSIGNOR, BY MESNE ASSIGNMENTS, TO WESTERN ELECTRIC COMPANY, INCORPORATED, A CORPORATION OF NEW YORK.

TELEPHONE-EXCHANGE SYSTEM.

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Specification of Letters Patent.

Patented May 3d, 1916.

Application filed March 16, 1915. Serial No. 14,718.

.a metering system wherein an electromagnetic charging means, such as a call register or coin Collector which is operated when a connection is established between a calling and an ordinary called subscribers line, is prevented from operating if the called sub scriber is a free subscriber. By a free subscriber is meant one calls to whom, are not to be charged against the calling subscriber.

Arrangements have been proposed in which calls to free subscribers lines are directed through special connecting means such as separate automatically operable connector switches, means being associated with said switches for preventing the actuation of a charging means. Insuch systems special connectors must be provided through which connections to free subscribers may be established. If a connection is directed through the other connector switches, the charging means will be operated. The setting aside of special connector switches for use in connections .to free subscribers lines is objectionable because these switches must be withdrawn from use in the general traffic.

According to the main feature of this invention, one and the same connecting means may be employed for extending the connection between a calling and a free or another subscribers line, means being provided for preventing the operation of the electromagnetic charging means only when said connecting means extends the calling line to a free called subscribers line.

In the preferred embodiment of this in vention the free subscribers lines lead through the contacts of a line finder switch and when such line is called for, the line finder starts to operate and causes the insertion of condensers in the established connecting circuit and therefore the ringing relay which is responsive to alternating current and is provided at the selector switch, becomes energized, but the apparatus controlling the actuation of the register or coin collector is prevented from operating.

1 Figures 1 and 2 represent diagrammatically certain parts of a telephone system, only so much being shown as is necessary to an understanding of the invention.

I Although this invention is shown and described as embodied in an automatic telephone system, it will be apparent to those skilled in the art that it is readily applicable to systems of widely varying character, such as semi-automatic telephone systems, manual telephone systems, etc.

Referring to the drawings, subscriber 1 desiring to obtain a connection with subscriber 2 removes his receiver from the switchhook and starts thereby line finder 3 to hunt for line 4-5 in any well known manner. After line finder 3 has found the calling line, subscriber 1 transmits by means of a. calling device 6, impulses representing the digits of the called subscribers number. The first set of impulses causes the selector switch 7 to select in any well known manner a certain trunk leading to the next selector in the series which may be the connector 8.

After the brushes 9 and 10 of selector 7 are arrested on terminals 11 and 12, a circuit is established from grounded battery 13 through the left-hand winding of relay 14, armature 15 and back contact of relay 16, terminal 12 and brush 10 of selector 7, brush and terminal of line finder 3, line 5, telephone substation of the calling subscriber, line 4, terminal and brush of line finder 3, coil of an electromagnetic charging means such asa polarized meter magnet 17, brush 9 and terminal 11 of selector 7, back contact and armature 18 of relay 16, and right-hand winding of relay 14 to ground. Relay 14 is energized, but the current flowing through this circuit is not of the proper direction to operate the meter magnet 17. Relay 14 by attracting its armature connects ground to one end of the winding of relay 19, and as the other end of the winding of this relay is connected to grounded battery, relay 19 becomes energized. Subscriber lproceeds now to send in the tens and units impulses for controlling the adjustment of the connector 8. In response to the first current interruption caused by calling device 6, relay 14 becomes deenergized and releases its armature, relay 19 however, being slow to re lease remains energized. A circuit is thereforeclosed from ground through the armature and back contact of relay 14, inner armature and front contact of relay 19 and the coil of slow acting relay 20 to grounded battery. Relay 20 by attracting its armatures closes a circuit from ground through armature and back contact of a marginal ringing'relay 21, conductor 22, outer armature and front contact of relay 20, conductor 23, energizing winding of slow acting escapement magnet .24 for the side switch to grounded battery. The slow acting magnet 24 becomes energized. In response to the next circuit closure produced by calling device 6, relay 14 becomes again energized and closes a circuit from ground through armature and front contact of relay 14, front contact and outer armature of mag net 24, side switch wiper 25, winding of rotary magnet 26 to grounded battery. In response to each energization of relay 14, magnet 26 causes the brushes 27, 28 and 29 of connector 8 to rotate onestep in front of a row of contacts in which subscribers lines terminate. Relays 19 and 20 and magnet 24 being slow to release stay up during the vibration of the armature of relay 14. After the last tens impulse has been sent out, relay 14 remains energized andmaintains open the circuit of slow acting relay 20. In response to the deenergization of relay 20, magnet 24 is also deenergized and opens atits outer armature and front contact the circuit of rotary magnet 26. Further, upon the deenergization of magnet 24, side switch wipers 25, 30, 31, 32 and 33 are moved to their second position.

In response to the circuit interruptions produced by subscriber 1 when sending out the units impulses, relays l4 and 20 and magnet 24 operate in the same manner as above described. In this instance, however, the vibration of the armature of relay 14 causes the operation of the vertical magnet 34 and causes the brushes of connector 8 to travel step by step over the previously selected row of terminals.

. After the last units impulse has been sent out and relay 14. is again energized, relay 20 releases its armature, opening the circuit of escapement magnet 24. The time elapsing between the deenergization of relay 20 and that of the slow magnet 24 is sufficient for the testing of the condition of the called line. If the called line is busy, test terminal 35 is connected to ground and a circuit is closed through brush 29, conductor 36,

wiper 33 (in position 2), conductor 37, back contact and inner armature of relay 20, offnormal contact 38 (closed as soon as connector 8 begins to travel in a vertical direction),.armature and back contact of relay 16, winding of release magnet 39 to grounded battery. The release magnet becomes energized in such event and causes the release of connector 8 to normal and the sending of a busy signal in the well known manner to the calling subscriber. Supposing however, that the called subscribers line idle, instead of ground, grounded battery is connected to terminal 35 through winding of cut-off relay 40, conductor 41 and winding of relay 42. Release magnet 39 does not become energized in the latter event and when'escapement magnet 24 deenergizes the circuit of vertical magnet 34 is opened and the side switch wipers are moved into their third position. A circuit is now closed from grounded battery through the winding of magnet 24, conductor 23, wiper 32, front contact and outer armature of relay 19, and back contact and armature of relay 21 to earth and back to battery. Magnet 24 becomes again energized. In the third position of the side switch wipers a circuit is closed for relays 40 and 42 from ground through wiper 33, conductor 36, brush 29 and terminal 35 of connector 8, conductor 41, winding of relay 42, conductor 41 and coil of relay 40 to grounded battery. This ground establishes a test guard on the multiple test terminals of the line of subscriber 2. Relay 42 upon energization closes a circuit from ground through its inner armature and front contact, conductor 43, normal contact 44, and left-hand winding of relay 45 to grounded battery. Relay 45 becomes energized and closes a circuit from ground through its outer armature and back contact and conductor 46 to winding of escapement magnet47 and grounded battery, and also to side switch wiper 48, conductor 49, back contact, armature and winding of stepping magnet 50 and grounded battery.

Magnets 47 and 50 become energized. Magnet 50 lnterrupts its owncircult and causes the stepping of brushes 51, 52, 53, 54 and 55 of switch 56 over a row of terminals 56'. Brushes 5155 and terminal'bank 56 are comprised in a selector switch 56 of a known design. To the terminals of this switch are connected the lines of the free subscribers.

As soon as brushes 51-55 leave their normal position, the normal contact 44 is opened and the circuit of relay 45 is broken. Relay 45, however, remains energized, a holding circuit for it being closed from grounded battery through right-hand winding. inner armature and front contact of relay 45, side switch wiper 57, brush 51 and terminal 58 to which ground is connected through the inner armature and back contact of a relay 42 included in the test wire 41 of each noncalling trunk. Therefore the circuits of relay 45 and of magnets 47 and 50- are maintained until brushes 51-55 reach terminals 59, 60, 61, 62 and 63. When this happens brush 51 does not find ground as relay 42 is energized, and therefore relay 45 deiinergizes, causing in turn the opening of the circuits of magnets 50 and 47. The brushes 51-55 are stopped on terminals 59 63 and magnet 47, upon deenergization causes side switch wipers 48, 57, 64, 65, 66, 67, 68 and 69 to move to their second position.

In position two of the side switch wipers a circuit is closed from ground through ringing generator 70 (Fig. 1) winding of ringing relay 21, armature and front contact of magnet 24, side switch wiper 31 (in position 3), brush 28 of connector 8 conductor 71, terminal 60, brush 52, side switch wiper 64 (in position 2), condenser 72, sideswitch wiper 65, brush 53, terminal 61, conductor 73, brush 27 of connector 8, side switch wiper 30, conductor 74 to ground The ringing relay 21 becomes energized, breaks the circuit of magnet 24 which deenergizes and causes the side switch wipers to move into their fourth position. The called subscriber 2 is not in this case signaled by ringing current produced by generator 70. At the same time a circuit is closed from earth through ringing generator 75 (Fig. 2) winding of a marginal ringing relay 76, conductor 77, side switch wiper 66, brush 54, terminal 62, line 78, the called subscribers station 2, line 79, terminal 63, brush 55, side switch wiper 67 to ground. The called subscriber is signaled now by ringing current supplied by generator 75, relay 76, however, being marginal becomes energized only when saidsubscriber answers, and opens the normally closed shunt around the coil of relay 80. Circuit is now closed from ground through side switch wiper 68, winding of relay 80, resistance 81 to grounded battery, and said relay by attracting its armature causes the deenergization of magnet 47 which allows the side switch wipers to move into the third position. In this position of the side switch wipers a circuit is closed from grounded battery through left-hand winding of relay 16, side switch wiper 31, brush 28 of connector 8, conductor 71, terminal 60, brush 52, side switch wiper 64, condenser 82, side switch wiper 67, brush 55, terminal 63, line 79, subscribers station 2, line 78, terminal 62, brush 54, side switch wiper 66, condenser 83, side switch wiper 65, brush 53, terminal 61, conductor 73, brush 27 of connector 8, side switch wiper 30, right-hand winding of relay 16, resistance 84 to ground. Condensers 82 and 83 being included in this circuit, relay 16 does not become energized and does not cause the reversal of the polarity of current flowing from grounded battery13 through the energizing winding of polarized meter magnet 17. Magnet 17 does not operate and the call is not charged against the calling subscriber 1.

Instead of, or in combination with the meter magnet 17, a polarized magnet 85 may be connected in series with line 4 at the calling subscribers station in connection with a coin collecting device. The current which traverses the windings of magnet 85 is not of the proper polarity and therefore in this case magnet 85 is not operated and the deposited coin is refunded to the calling subscriber. Subscribers 1 and 2 can enter now into conversation, current being supplied to the called subscribers station from grounded battery through the righthand winding of relay 86, side switch wiper 67, subscribers loop, side switch wiper 66 and the left-hand winding of relay 86 to ground and back to battery; and to the calling subscriber, from grounded battery 13 through the left-hand winding of relay 14 and back through the right-hand winding of relay 14 to ground.

After the conversation is finished and subscribers 1 and 2 restore their receivers, line finder 3,'selector switch 7 and connector 8 are released to normal in the well known manner. l/Vhen connector 8 returns to normal, relays 42 and 40 become deenergized. In response to the de'energization of relay 42 a circuit is closed from ground through the outer armature and back contact of relay 4, conductor 86, off-normal contact 87, winding of release magnet 88 to grounded battery. The release magnet 88 becomes energized and causes switch 56 to return to normal.

In the drawings .only one switch 56 is represented. It is obvious, however, that a plurality of such switches may be provided in connection with the subscribers lines. In this case the starter wire 43 and conductor 86 are extended by means of an allotter to a free switch 56 in the well known manner. When a connection is established the first idle switch 56 will be caused to seize the called subscribers line.

If subscriber -1 desires to obtain a connection with another subscriber, than a free subscriber, for instance with a subscribers line 90, 91, he sets the brushes of connector 8 on the contacts in which lines 90, 91 and test conductor 92 terminate. In this case, however, when side switch wipers 30 and 31 are in their third position, the ringing current is transmitted to the called subscriber due to the fact that no condensers like condenser 72 is included in the above traced circuit of the ringing relay 21. Ringing current will therefore be transmitted to the called subscriber and when the called subscriber answers and ringing relay 21 in the same manner as relay 76 becomes energized and escapement magnet 24 deenergizes, the side switch wipers are moved into their fourth position. Relay 16 is now energized as no condensers like condensers 82, 83 are included in its circuit. Relay 16, by attracting its armatures 15 and 18 reverses the current flowing through the windings of meter magnet 17 and coin box magnet 85. Meter magnet 17 upon energization causes the registration of the call in the well known manner and polarized magnet 85 causes the money to be deposited in the coin box.

WVhat is claimed is:

1. Ina telephone system, a plurality of subscribers lines, means for establishing a connection between a calling and acalled line, electromagnetic charging means adapted to be operated after the establishment of said connection, switching means, means for extending a called line to said switching means upon the establishment of a connection, and means operative thereupon to prevent the actuation of said electromagnetic charging means.

2.- In a telephone system, a plurality of subscribers lines, means for establishing a connection between a calling and a called line, electromagnetic charging means adapted to be operated after the establishment of a connection, a switching means, an automatic switch mechanism for extending a called line to said switching means, and means operative thereupon, for preventing the actuation of said electromagnetic charging means.

3. Ina telephone system, a plurality of subscribers lines, automatic switches for establishing a connecting circuit between a calling and a called line, a polarized meter magnet included in said connecting circuit, means controlled by the called subscriber for energizing said meter magnet, a switching means, an automatic switch mechanism for extending a calling line to said switching means, and means operative upon the establishment of said connecting circuit for preventing the actuation of said polarized meter magnet;

. 4. In a telephone system, a plurality of subscribers lines, a plurality of free subscribers lines, means for establishing a connection between a calling and called subscribers line, electromagnetic charging means adapted to be operated upon the establishment of a connection, a switching means, means for extending a called free subscribers line to said switching means and means operative thereupon to prevent the actuation of said electromagnetic charging means. I

5. In a telephone system, a plurality of subscribers lines, means for establishing a talking circuit between a calling and a called line, polarized charging means in- .cluded in said talking circuit, a relay adapted to be energized under the control of the called subscriber and controlling in turn upon energization the actuation of said polarized charging means, an automatic switch mechanism operated prior to the establishment of the talking circuit, and means controlled by said automatic switch mechanism to prevent the energization of said relay.

6. In a telephone system, a plurality of subscribers lines, automatic switching mechanisms for establishing a connecting circuit between a calling and a called line, polarized charging means connected in series with said connecting circuit at the calling end thereof, a relay connected in series with the called end of said connecting circuit and controlling upon energiza-tion the actuation of said charging means, an automatic switch, stationary contacts for said automatic switch in which said subscribers lines terminate, movable contacts for said automatic switch, a condenser adapted to be connected to the movable contacts of said switch, means for causing said automatic switch to engage with its movable contacts the stationary contacts in which the called subscribers line terminates, and means operative thereupon to insert said condenser into the called end of said connecting circuit for preventing the energization of said relay.

7 In atelephone system, the combination with lines, switches, charging apparatus for lines when calling, and means adapted to operate said apparatus when calling lines are connected by said switches to lines called for, of automatically operating means for disabling the apparatus operating means when calling lines are connected by said switches to certain of said lines.

8. In a telephone system, the combination with lines, an automatic connector, charging apparatus for lines when calling, and means adapted to operate said apparatus when calling lines are connected by said connector to lines called for, of automatically operating means for disabling the apparatus operating means when calling lines are connected by the said connector to certain of said lines.

9. In a telephone exchange system, incoming and outgoing lines, a switch for extending an incoming line to an outgoing line, an electromagnetic charging means adapted to be operated over said extended line, means for preventing the operation of said charging means, and a mechanism for connecting said last mentioned means to the extended line.

10. In a telephone exchange system, incoming and outgoing lines, a switch for extending an incoming line to an outgoing line, an electromagnetic charging means adapted to be operated over said extended line, means for preventing the operation of said charging means, and a switching device adapted to automatically hunt for and seize the extended line for connecting said last mentioned means thereto.

In Witness whereof, I hereunto subscribe my name this 15th day of March A. D.,

. CHARLES L. GOODRUM.

Witnesses:

E. EDLER, K. L. STAHL. 

